Ever wondered what all those letters mean when you hear a Harley model number? Well here is the answer. I found this a while back when I was looking to buy a bike. I don’t remember where I found it, so unfortunately I can not give credit to the original author.

 

The first letter of the model designator reveals the engine series:

 

First character:

G - Servicar three wheeler, 1932 to 1972

E - Overhead valve 61 cubic inch "big twin" (Engine/trans separated)

F - Overhead valve 74 or 80 cubic inch "big twin"

K - Side valve 45 and 55 cubic inch sports bike that replaced the WL in 1953 and was replaced by the sportster in 1957. It had many design features that were carried over to the Sportster.

U - Side valve 74 or 80 cubic inch "big twin"

V - Side valve 74 cubic inch made prior to 1936

W - Side valve 45 cubic inch made 1934 to 1952

X - Sports and special construction. Applied to 1918-1922 opposed twin
Sport, 1944 military opposed twin, and 1957 to present Sportster. There were others, such as the J series (a very nice looking bike that was about the hottest thing around in the 20's) but you're not likely to see them in daily use anymore.

Second character:

L - high compression. Omitted on low compression early models, and not indicative of compression on current models.

Remaning characters:

Model descriptions, eg WG - Wide Glide. Some generalizations:

A - Military (Army) version (except GA, Servicar without tow bar)

B - Battery start (early models), Belt drive (some later models).

C - Classic, Competition, Custom, various others meanings.

D - Dyna, the newest frame and engine mount design.

E - Electric start

F - Foot shift (when the standard was hand-shift)

H - varied between High performance and Heavy duty. The early FLH for example produced 5 more HP than the FL and was used primarily for touring and sidecar applications.

LR- Low Rider (though many Low Riders don't include LR in the model ID)

P - Police version

R - Rubber mounted engine (some models) racing version (other models) e.g. the FXR is a lowrider with rubber mounted engine, WLR is the flat track racer that was very hard to beat in the 30's, 40's, and 50's.

ST- Soft Tail

S - (without following T) Sports version eg FLHS is an FLHT without the touring package.

T - Touring

WG- Wide Glide

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Sportsters: Models beginning with X are Sportsters. These descend from the K series, 1952-56. The XL series started in 1957. They are "unit construction" (engine & transmission share a common case). X was in the normal series, following the U and V used for flathead Big Twins.

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L stood for high compression (7.5:1 in 1957). In 1958 came the XLH with H meaning Higher-power or High-compression (9:1) or Hot. Also in 1958 was the XLCH: The C in XLCH was intended to mean "Competition", but the late Hal Robinson used to claim the CH on his bike stood for Charley Horse" because it was highly modified and had enough initial  ignition advance to kick back rather severely.

The Sportster engines were originally actually 53.9ci. (883cc) but were designated as 55ci. This was upgraded (in 1970?) to 61ci (1000cc), redesigned in '73 but still 61" and stayed relatively unchanged until the 74" EVO version. The 883 and 61" were both  produced the first year of the 883. Options for Sportsters abounded but these same letters have been used since 1958 in various combinations, plus the XLCR (a "cafe racer" style, with bikini fairing) and the XLT (Touring, with bigger tank, thicker seat, and hard bags straight off the FLHS), both produced 1977-1978 only.

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Big Twins: Models beginning with F are Big Twins. These all descend from the 61E in 1936. Knuckleheads 1936-47, Panheads 1948-65, Shovelheads 1966-84/85, and Evolutions 1984/5-present. The Evolution (block head) was introduced in '84 on the Soft Tail and Tourglide Ultra, with the last Shovel built in mid '85. Until 1978, these were mostly 74's (~1200cc). In 1978, the 80ci (~1340cc) was introduced.

 

In 1971 was the first FX model, with an F engine and assorted Sportster (X) parts, notably forks - these were initially Super Glides. In 1974,  FXE was Electric start. In calendar 1977 came the FXS Low Rider, with shortened shocks and scooped seating position. Also in 1978, the FX Super Glides got belt final drive. 1979 brought 80ci Shovelheads and the FXEF Super Glide Fat Bob (not Boy), for bobbed fenders and fat tank. In 1980, FXWG (Wide Glide) and the FXB Sturgis with belt drive (primary and secondary).

1984 brought the Softtail FXST, with the look of an old hardtail but some suspension for comfort.
 

In 1991 came the FXD Dyna Glide series, starting with another Sturgis model. This brought many frame and engine mounting changes, a relocated oil tank and moved crossover pipe.

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Touring: In 1980, the FLT designation was introduced for the Tour Glide. This model introduced the vibration-isolation mounted engine (rubberglide) and also a slightly different frame from other FLs and a fixed fairing. FXR (originally called Super Glide II) arrived in late 1981. The R had rubbermount engine and 5-speed tranny, as opposed to rigid-mount and 4-speed in other models. FXRS maybe meant Sport, with cast wheels and a small sissy bar. The Sport Glide FXRT (Touring) arrived in 1983, with the fixed fairing and air adjustable anti-dive forks.
 

 

The only really reliable letters now are at the beginning of the model: X=Sportster, F=Big Twin, FL=Big Twin with big forks, FX=Big Twin with Sportster-style (smaller) forks, FXST=Softtail, FXD=Dyna  Glide. At times, different models have even shared the same letter-designation; witness the FLHTC Electra Glide Classic/Ultra Classic Electra Glide in 1993 models.